The present invention relates generally to seat restraint systems for vehicles and, more particularly, to a tension sensing assembly for a seat restraint system in a vehicle.
It is known to provide a seat restraint system such as a seat belt in a vehicle to restrain an occupant in a seat of the vehicle. In some vehicles, the seat restraint system may be a lap belt, a shoulder belt, or both. Typically, the lap belt and shoulder belt are connected together at one end. The seat restraint system includes a latch plate at the connected end. The seat restraint system also includes a buckle connected at one end by webbing or the like to vehicle structure. The buckle receives the latch plate to be buckled together. When the buckle and latch plate are buckled together, the seat restraint system restrains movement of the occupant to help protect the occupant during a collision.
Smart inflatable restraint systems need to know what is occupying a seat of the vehicle. Decisions on deployment of inflatable restraints depend on information supplied by sensors in the seat in determining weight of an object in the seat. When a child seat is placed in the seat and cinched down, the sensors may read a large mass instead of a child seat. With this condition, there will be high tension in the seat restraint system. Comfort studies have shown that no human occupant would wear their seat restraint that tight. With this information on seat restraint tension, the inflatable restraint system can decide on deployment of the inflatable restraints.
Therefore, it is desirable to provide an assembly for sensing tension in a seat restraint system of a vehicle. It is also desirable to provide an assembly for sensing tension in a seat restraint system in a vehicle that allows a control module to determine the difference between either a child seat or a small occupant. It is further desirable to provide an assembly for sensing tension in a seat restraint system in a vehicle that eliminates belt load passing through the sensor and provides an indication of high-tension forces in the seat restraint system. It is still further desirable to provide an assembly for sensing tension in a seat restraint system that can be replaced without replacing the complete buckle assembly. Therefore, there is a need in the art to provide a tension sensing assembly that meets these desires.
It is, therefore, one object of the present invention to provide a new tension sensing assembly for sensing tension in a seat restraint system of a vehicle.
It is another object of the present invention to provide an assembly for tension sensing in a seat restraint system of a vehicle that eliminates belt load passing through the sensor.
It is yet another object of the present invention to provide an assembly for tension sensing in a seat restraint system of a vehicle that can be replaced without replacing a buckle assembly.
To achieve the foregoing objects, the present invention is a tension sensing assembly for a seat restraint system in a vehicle including a sensor plate adapted to be fixed relative to vehicle structure and a movable anchor plate adapted to be connected to a portion of the seat restraint system and movable relative to the sensor plate. The tension sensing assembly also includes a housing mounted to the sensor plate and a movable actuator disposed in the housing. The tension sensing assembly also includes at least one spring disposed between the housing and the actuator. The tension sensing assembly includes at least one magnet mounted to either one of the actuator and the housing and a Hall effect sensor mounted to either one of the housing and the actuator and cooperable with the at least one magnet. The anchor plate includes a tab portion extending through the housing and cooperable with the actuator to move the actuator to deflect the at least one spring. The actuator moves to change a distance between the at least one magnet and the Hall effect sensor to change an output of the Hall effect sensor to indicate a tension level in the seat restraint system when the at least one spring is deflected.
One advantage of the present invention is that a new tension sensing assembly is provided for a seat restraint system in a vehicle. Another advantage of the present invention is that the tension sensing assembly senses tension in the seat restraint system to help identify what is occupying the seat, either a child, child seat, or low mass adult. Yet another advantage of the present invention is that the tension sensing assembly is non-load bearing by removing a belt load path through a sensor thereof. Still another advantage of the present invention is that the tension sensing assembly allows the sensor to be replaced without replacing a complete buckle assembly. A further advantage of the present invention is that the tension sensing assembly can have angular or offset loading that does not affect operation of the sensor.